Orthogonal frequency division multiplexing (OFDM) is a form of multiplexing that distributes data over a number of carriers that have a very precise spacing in the frequency domain. The precise spacing of the carriers provides several benefits such as high spectral efficiency, resiliency to radio frequency interference and lower multi-path distortion. Due to its beneficial properties and superior performance in multi-path fading wireless channels, OFDM has been identified as a useful technique in the area of high data-rate wireless communication, for example wireless metropolitan area networks (MAN). Wireless MAN are networks to be implemented over an air interface for fixed, portable, and mobile broadband access systems.
In some wireless networks, a mobile station (MS) in a given cell is only served by a single base station (BS). One drawback of such wireless networks is that MSs near an edge of the given cell suffer performance loss due to interference from other cells in cellular networks and propagation loss in non-cellular networks.
OFDM may be used for broadcast, multicast or unicast traffic. Broadcast traffic is for reception by all access terminals (i.e. one point to all points), multicast traffic is for multiple, but not necessarily all access terminals (i.e. one point to two or more points), and unicast traffic is for individual access terminals (i.e. one point to another).